The present invention relates to a novel chain drive system for incorporation into a construction toy system, for use in driving movable parts located remotely from the drive input, for conveying elements from one location to another, etc. The drive system of the invention is most usefully incorporated in and combined with elements of the above mentioned Glickman patents.
The chain drive of the invention includes a novel chain link construction, in which each link, formed of injection molded structural plastic, is of a generally U-shaped configuration. The link element includes a pair of spaced-apart side elements, which are laterally notched adjacent their outer ends. The "base" portion of the U-shaped link has cylindrical bearing portions adapted for snap-in assembly with the notched side elements of an adjacent link. Once the snap-in assembly has been effected, the adjacent links are semi-permanently connected but can easily pivot about a transverse axis in the manner of a conventional link chain. The arrangement enables a drive chain to be assembled of any length suitable for the particular application. Disassembly is, of course, equally efficient. The chain structure is strong, extremely lightweight and, as will appear, highly versatile.
In a particularly preferred embodiment of the invention, each of the individual chain links, at its base, includes outwardly projecting drive pins at each side, axially aligned with the cylindrical bearings by which an adjacent link is connected. The spacing of adjacent sets of drive pins on successive links corresponds with the spacing between a predetermined number of teeth of a drive gear. In the preferred embodiment of the invention, a pair of such gears are mounted on a shaft in predetermined spaced-apart relation equal to the overall width of the chain links, as defined by the spaced-apart side elements. The respective gears are secured to a supporting shaft and provide a driving connection between the chain and the shaft. Opposed pairs of drive pins progressively seat in grooves, formed between successive teeth of the gears, providing a particularly advantageous form of driving connection between the chain and the gears.
In another preferred embodiment of the invention, the base portion of each chain link includes, in addition to the cylindrical bearing portions previously mentioned, a central coupling portion which is transversely grooved to accommodate snap-in assembly of a connector element of a type disclosed in the before mentioned U.S. patents. By assembling a connector element with selected links of a chain assembly, it is possible to provide additional driving functions, such as moving of parts on a conveyor structure, advancing vehicles up an incline for a roller coaster structure, etc.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of a preferred embodiment of the invention and to the accompanying drawings.